Mflp-valve for a pressure source

ABSTRACT

A mechanical fluid pressure modification valve, or “MFLP-valve”, is set forth. The MFLP-valve can be actuated upon movement of a movable pressure system member of a medical pressure system reaching a selected position. Additionally, the MFLP-valve can be actuated based on a pressure condition of the system. When the MFLP-valve unseals, a pressure differential between a pressure chamber and a volume outside of the chamber can be relieved. Disengagement of the movable pressure system member from the MFLP-valve can enable the MFLP-valve to re-seal. The MFLP-valve may include a flag that indicates the position of the movable pressure system member. The MFLP-valve may be provided in a diaphragm-type pressure source.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/205,419 filed Aug. 14, 2015 entitled “MFLP-Valve for a PressureSource,” the entire disclosure of which is hereby expressly incorporatedby reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to pressure systems, such asbreastmilk expression systems, including breastpumps, and, moreparticularly, to a mechanical fluid pressure modification valve(hereinafter MFLP-valve) that provides relief and/or intake for fluid ina pressure system, and that may be used in combination with a flagselectively detected by a sensor.

BACKGROUND

Pressure systems, such as breastmilk expression systems, have beendisclosed that include mechanisms to selectively modify pressure withinthe system. For instance, U.S. Pat. No. 5,007,899 discloses a breastpumpwith a piston pump having an aperture in a piston cylinder. Thebreastpump exposes the vacuum generating chamber to atmosphere when thehead of the piston passes beyond the aperture. This returns the chamberto ambient pressure and limits peak negative pressure.

U.S. Pat. No. 8,070,715 discloses a breastpump system having a solenoidvalve provided in an ambient airline. The solenoid valve is operated bya controller to open when a vacuum in a breastshield of the breastpumpsystem reaches a desired pressure, permitting the vacuum within thebreastshield to decrease (in other words, permitting the pressure in thebreastpump system to increase) toward ambient pressure. However, insteadof allowing the vacuum to decrease all the way to ambient pressure, thebreastpump is further provided with a regulator that closes duringbreastpump operation once the system reaches a preset minimum vacuumlevel.

The known pressure control mechanisms may require more than desireddesign complexity. For example, the piston-cylinder/aperture design maylimit the overall performance of the system. The solenoid valve needs tobe powered directly. The solenoid valve also adds cost to the system,and may generate undesirable noise in the system. For these and otherreasons, previously-designed pressure control systems may introducelimitations for optimizing the design.

SUMMARY OF THE DISCLOSURE

In accordance with the principles of the present disclosure, amechanical fluid pressure modification valve, or MFLP-valve, is setforth. One or more MFLP-valves can be customized, or tuned, to fine tunefluid flow in a pressure system. The MFLP-valve may be integrally formedwithin a surface of the pressure system. The MFLP-valve can be formed ofan expandable material, and can be vented or selectively vented. Forexample, where the MFLP-valve is an expandable member, the expandableportions of the MFLP-valve can include one or more vents that only openupon expansion of the MFLP-valve, thereby selectively venting thesystem. The MFLP-valve can be non-electric.

The MFLP-valve may comprise an operable cover configured to cause apressure condition in the system. The operable cover may be disposedabove an aperture of the pressure system and may be composed of alightweight material. The operable cover of the MFLP-valve may beconnectable to the pressure system to modify system pressuretherethrough, for example, to vent the system to ambient pressure. Theoperable cover may achieve this by having one or more vents formedwithin the operable cover, the vents configured to enable fluid flowinto or out of the pressure system. The vents may be expansion vents,which are vents that open when the operable cover moves, or reliefvents, or both. The operable cover may be configured to open based on amechanical change in the pressure system.

The MFLP-valve, and specifically the operable cover, can incorporate apost that can be selectively engaged by a movable pressure systemmember. The MFLP-valve can provide both relief and intake in a pressuresystem. The pressure system may act as a closed pressure system, exceptwhen the MFLP-valve is active. Additionally, the MFLP-valve can provideinformation regarding a state of the pressure system. To this end, oneor more suitable detection devices, such as a sensor (such as aphotoelectric sensor or a Hall effect position sensor) or switch, can beincorporated into the pressure system to determine an operating state ofthe MFLP-valve, based on an open or closed state of the MFLP-valve. Thestate determination can be made directly based on sensing the state fromthe MFLP-valve position or from a position indicator extending from theMFLP-valve. Alternatively, the state determination can be madeindirectly based on a cooperating position member whose movement iscoordinated with changes in state of the MFLP-valve and detected by oneor more detection devices.

In an exemplary embodiment constructed in accordance with the principlesof the present disclosure, a pressure system, such as a breastmilkexpression system, can include one or more MFLP-valves attached to thepressure system, such as along a pressure generating chamber of thesystem. The MFLP-valve can provide a vent from an interior of thechamber to fluid outside of the chamber. The MFLP-valve can operatebased on movement of a movable pressure system member, such as apressure source or other system component, or member, for which anoperational state can be monitored based on the movement of thecomponent. The MFLP-valve may be used to initialize the pressure source.The desired base pressure may be atmospheric pressure. Alternately, thedesired base pressure may be a pressure other than atmospheric pressure.The MFLP-valve can also be configured to serve as a pressure reliefmechanism that does not require contact with the movable pressure systemmember.

One example of why the desired base pressure might differ fromatmospheric pressure is to minimize repetitive friction on a nipple asit is received in a nipple tunnel of a breastshield during repeatedcycles of a vacuum source. For example, it has been observed that whenan infant is properly latched onto a mother's breast during feeding, thenipple is held in a substantially constant depth in the infant's mouthrelative to the junction of the hard and soft palette. In an effort tomimic this natural action, it may be desirable to hold at least aminimum vacuum that is less than atmospheric pressure, during successivecycles of the vacuum.

A MFLP-valve constructed in accordance with the principles herein canoperate by movement of a movable pressure system member of a pressuresource. In an exemplary embodiment, the MFLP-valve can provideverification of a position of the movable pressure system member whenactuated. To this end, a MFLP-valve constructed in accordance with theprinciples herein can include structure or related components in thepressure system, any of which can be configured to provide conditionstate information to one or more detection devices or systems in thepressure system.

For example, in one embodiment, the MFLP-valve can include an extension,such as a flag, configured to selectively engage a sensor dependent upona position of the flag relative to the position of the movable pressuresystem member. The flag can be operably connected to and/or extend froman operable cover of the MFLP-valve. In one embodiment, engagementbetween the flag and the sensor indicates that movable pressure systemmember is in a desired position indicative of an operating condition.For example, when the movable pressure system member is in a positionthat causes the MFLP-valve to be in an open position, the flag on theMFLP-valve may be moved into a location in which it can be sensed by asensor, such as by having a beam of light hit the flag. In anotherembodiment, dis-engagement between the flag and the sensor indicatesthat the movable pressure system is in a desired position indicative ofan operating condition. For example, the flag may have a hole or port init. The flag may normally be engaged with the sensor (for example, bybeing hit by a beam of light), but movement of the MFLP-valve inresponse to the location of the movable pressure system member may causethe sensor to disengage with the flag (for example, by having the beamof light pass through the hole.) In this embodiment, the dis-engagementbetween the flag and the sensor indicates the position of the movablepressure system member. In yet another embodiment, the flag can beconfigured to engage a switch or other component when a desired positionindicative of an operating condition is reached by the flag in thesystem.

In another embodiment, a sensor may be capable of sensing more thanwhether the flag is engaged or disengaged with the sensor and canprovide more detailed information about the location of the movablepressure system member. For example, different and specific stripes on aflag, where each specific stripe corresponds with a certain position ofthe movable pressure system member, may be sensed by a sensor and usedto provide specific information about the location of the movablepressure system member. By using this or similar techniques, the speedat which the pressure system member is moving can also be determined ifdesired.

In still another embodiment, the flag can be configured to indicate amechanical state change, such as whether the pressure system is open orclosed, in the pressure system to a detection device or detectionsystem. In other embodiments, or in combination with one or moreembodiments herein, the flag can be configured to verify the output ofother sensors incorporated into the system, including, but not limitedto position, speed, pressure and/or state change sensors. In a furtherembodiment, the MFLP-valve can be formed of elastic and/or expandablematerial configured to be movable between a closed state and an openstate, where the flag either opens or expands and the detection deviceor detection system is configured to detect the open state of theMFLP-valve. Examples of suitable elastic and/or expandable materials caninclude elastic, rubber, spring-like material, or any other expandablematerial. Alternatively, the detection device or detection system can beconfigured to detect the closed state of the MFLP-valve.

In yet another embodiment, an associated component of the system can beconfigured to relay the position of the MFLP-valve to the detectiondevice or detection system, so that a direct sensing of the MFLP-valveor a flag extending therefrom, is not required. The flag or associatedcomponent indicating a state condition to a detection device ordetection system can indicate any position information desired from thesystem, or a pressure change or condition.

A MFLP-valve constructed in accordance with the principles of thepresent disclosure can be varied, adjusted, customized, or tuned, asdesired, by changing the geometry and/or material properties of theMFLP-valve in order to adjust, for example, the force required to openthe MFLP-valve and/or the response of the position indicator. In thismanner the accuracy, precision, sensitivity, or other parameter(s) ofthe MFLP-valve can be selected to suit a particular pressure system. Forexample, sealing characteristics of the MFLP-valve can be tuned byadjusting the material and/or geometry of the MFLP-valve. In addition,fluid flow rate for the system can be varied by varying the number andsize of relief apertures, or vents, provided in the MFLP-valve. Stillfurther, the relief apertures, or vents, can be selectively openable,such as by expanding the MFLP-valve, if desired. In accordance with amethod of manufacture, sealing capabilities of the MFLP-valve can beselected based on performance capabilities or other configurations ofthe system, including pressure parameters of the system as well as aselection of the number of MFLP-valves to be used in a system. As yetanother example, the MFLP-valve may be tuned and configured to open witha delayed action when the movable pressure system member engages theMFLP-valve, and the MFLP-valve may further being tuned and configured toremain open with a delayed action before returning to a first, sealedposition when the movable pressure system member is disengaged from theMFLP-valve. The MFLP-valve can be constructed so as to change shape inresponse to changing pressure or the movable pressure system member, andthe shape change may create an opening that relieves system pressure orindicate a change in the position of the movable pressure system member.The tuned properties of the MFLP-valve may be collectively referred toas the “tuning condition”.

In accordance with the principles herein, the system can include aMFLP-valve that includes a preset tuning condition, determined prior tomanufacturing of the system. In another embodiment, the system can betuned by altering properties of the MFLP-valve during the manufacturingprocess, including on unit by unit basis, if desired. In still anotherembodiment of the system, the tuning condition of the MFLP-valve can belinked to the pressure system's mode of operation at any given time,such that the user may directly or indirectly change the MFLP-valvetuning condition as the systems mode of operation is changed. Changes tothe tuning condition of the MFLP-valve can be reversible, if desired.

According to embodiments within the scope of the present disclosure, amedical pressure system includes a mechanical fluid pressuremodification valve, referred to herein as a “MFLP-valve,” thatselectively seals and unseals an aperture through which, when unsealed,a pressure differential between a pressure chamber within the pressuresystem and a volume outside of the pressure system is minimized until adesired pressure is obtained; a controller in operable communicationwith a pressure source of the pressure system; and a flag connected tothe MFLP-valve, the flag configured to trigger at least one of (1)modify operation of the pressure source upon motion of the MFLP-valvebetween a sealed condition and an unsealed condition, and (2) verify aposition of a movable pressure system member of the system.

The flag may be directly attached to the MFLP-valve. Alternately, theflag may be indirectly attached to the MFLP-valve. The MFLP-valve mayinclude a gasket to seal the aperture. In sealingly engaging a wall ofthe pressure source about a perimeter of the aperture, the gasketsealingly engages an end wall of the pressure source.

A breastmilk expression system of the present disclosure includes aMFLP-valve configured to minimize a pressure differential between apressure generating chamber and a volume outside the pressure generatingchamber through an aperture; and a movable pressure system memberdisposed in the system, the movable pressure system member configuredfor movement between a first position and a second position, theMFLP-valve actuable to an open position upon the movable pressure systemmember reaching the second position and the MFLP-valve indicating aposition to a sensor in the system. The MFLP-valve may be furtherconfigured to reach the open position to minimize a pressuredifferential irrespective of the position of the movable pressure systemmember. The aperture may be disposed within the pressure generatingchamber, the MFLP-valve being actuable between a first, sealed positionsealing the aperture and a second, open position unsealing the aperture.

The MFLP-valve may be configured to open when the movable pressuresystem member engages the MFLP-valve and the MFLP-valve may be furtherconfigured to return to the first, sealed position when the movablepressure system member is disengaged from the MFLP-valve. The MFLP-valvemay be tuned and may open with a delayed action when the movablepressure system member engages the MFLP-valve, and the MFLP-valve mayfurther be tuned and may remain open with a delayed action beforereturning to the first, sealed position when the movable pressure systemmember is disengaged from the MFLP-valve. The MFLP-valve may include apost extending through the aperture, the movable pressure system memberbeing a reciprocating member, the post being engaged by thereciprocating member when the reciprocating member is in the secondposition.

The MFLP-valve may further include a membrane surrounding the post, themembrane having a surface area greater than an area of the aperture inthe pressure generating chamber through which the post extends, suchthat upon disengagement of the post by the reciprocating member, themembrane closes over the aperture.

The MFLP-valve may further include a membrane surrounding the post, themembrane having a surface area greater than an area of the aperture inthe pressure generating chamber through which the post extends, and agasket depending from the membrane such that upon disengagement of thepost by the reciprocating member, the gasket sealingly engages thepressure generating chamber about a perimeter of the aperture.

The MFLP-valve may include a living hinge, the living hinge hingedlysecuring the membrane to a portion of the MFLP-valve secured to the wallof the pressure generating chamber.

A breastmilk expression system of the present disclosure includes aMFLP-valve responsive to a mechanical force applied thereto, theMFLP-valve configured to open as a movable pressure system memberarrives at a selected position and operably connects to the valve,thereby providing the mechanical force applied to the MFLP-valve.

A MFLP-valve of the present disclosure may include an operable coverconnectable to a pressure chamber within a medical pressure system,configured to cause a pressure condition in the system upon movement ofa movable pressure system member, and operably connected to a flag; andthe flag may be configured to indicate a position of the movablepressure system member in the pressure system. The operable cover may beconnectable to the pressure chamber within the pressure system tominimize a pressure differential between the pressure chamber and avolume outside of the pressure chamber.

The flag may be configured to selectively engage a sensor dependent on aposition of the flag relative to the position of the movable pressuresystem member. The MFLP-valve may additionally include one or more ventsconfigured to enable fluid flow into or out of the pressure chamberwithin the pressure system. Such vents may be formed in the operablecover, and the vents may be further defined by at least one ofexpandable vents and non-expandable vents.

The flag may be connected to, and extend from, the operable cover. Theoperable cover may further be configured to open based on a mechanicalchange in the pressure system.

A medical pressure system of the present disclosure includes aMFLP-valve including a operable cover connectable to a pressure chamberwithin the pressure system, and operably connected to a flag; and theflag configured to provide an indication of a position of a movablepressure system member in the system.

The medical pressure system may be a breastmilk expression system. Themedical pressure system may further include a breastpump having a vacuumgenerating chamber. The vacuum generating chamber may include anaperture. The operable cover may be disposed above the aperture.

The operable cover may be dimensioned of a flexible material andconfigured to change pressure within the system upon operating.

The operable cover may further include a post, the vacuum generatingchamber further including a movable pressure system member configured toselectively engage the post based on a position of the movable pressuresystem member within the vacuum generating chamber.

The vacuum generating chamber may further include a movable pressuremember having a post, the post selectively engaging the operable coverbased on a position of the movable pressure system member within thevacuum generating chamber.

A MFLP-valve of the present disclosure may include an operable cover;and a post connected to the operable cover and configured to extend intoa fluid flow section of a medical pressure system, the post configuredto engage an aperture of the pressure system during operation of thepressure system, the operable cover via the post configured toselectively open the aperture based on at least one of a position of amovable pressure system member in the system and a pressure condition inthe pressure system. The pressure system used in connection with theMFLP-valve may be a breastpump, and the MFLP-valve may include a flagconnected to the operable cover and configured to selectively engage asensor when the movable pressure system member of the pressure system isin a desired position. The MFLP-valve may be configured to prevent fluidexchange through the MFLP-valve unless at least one of a selectedposition of the movable pressure system member in the pressure systemhas been reached and a pressure condition in the pressure system hasbeen reached. At least one of the geometry, material properties, ormating properties of the MFLP-valve can be adjustable to tune theaccuracy, precision, sensitivity, or other parameter associated with theMFLP-valve upon a change in a mode of operation of the system. TheMFLP-valve may be constructed so as to change shape in response tochanging pressure or interaction with the movable pressure systemmember, and either the shape change creates an opening that relievespressure in the pressure system or the shape change indicates a changein the position of the movable pressure system member. Moreover, amulti-pump system can be operated in accordance with the principles ofthe present disclosure.

The MFLP-valve may be integrally formed within a surface of the pressuresystem. The MFLP-valve may include a flag connected to an extending froma surface thereof.

A breastmilk extracting system of the present disclosure may include apressure source configured to selectively activate one or moreMFLP-valves based on the systems mode of operation. Such a breastmilkextraction system may be provided wherein each of the one or moreMFLP-valves are configured for selective tuning to adjust fluid flow inthe system based on a state of operation of the system. A breastmilkextracting system of the present disclosure may include an MFLP-valveoperably connected to a pressure chamber of the system, the MFLP-valveconfigured to unseal to relieve a pressure differential between apressure chamber of the system and a volume outside of the chamber byallowing fluid in the system to flow in and out of the MFLP-valve whenthe MFLP-valve unseals.

A system for extracting milk from a lactating human mother according tothe present disclosure may include a breastpump, a pressure generatingdevice including at least one of a piston and a diaphragm that generatespressure in the system, and a MFLP-valve that physically opens when thepressure generating device arrives at a return position at an end of astroke of the pressure generating device. The pressure generating devicephysically opens the valve at the end of the stroke to connect thepressure in the system with external pressure, allowing the pressure inthe system to equalize with external pressure or reducing a pressuredifferential between the system and external pressure.

An alternate embodiment of a pressure source of the present disclosuremay include a diaphragm membrane, a rigid cap, a movable pressure systemmember associated with the diaphragm membrane that actuates thediaphragm membrane between a first position away from the rigid cap anda second position toward the rigid cap, and a MFLP-valve including anoperable cover and a post connected to the operable cover, the postconfigured to engage an aperture of the pressure source during operationof the pressure source, the operable cover via the post configured toselectively open the aperture based on a position of at least one of themovable pressure system member and the diaphragm membrane. In such apressure source, the aperture may be provided in the rigid cap, in whichcase the MFLP-valve is associated with the rigid cap, and the postextends through the aperture, so as to seal the aperture when thediaphragm membrane is not in contact with the post. Alternatively, theaperture may be provided in the diaphragm membrane, in which case theMFLP-valve is associated with the diaphragm membrane, and the postextends through the aperture, so as to seal the aperture when the postis not in contact with the rigid cap.

These and other advantages can be accomplished by a MFLP-valveconstructed in accordance with the principles herein, as discussed inthe following detailed description of the exemplary embodiments, withreference to the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary pressure source providedwith an exemplary embodiment of a MFLP-valve constructed in accordancewith the principles of the present disclosure;

FIG. 2 illustrates an exemplary embodiment of an MFLP-valve incombination with a chamber of a pressure source having a movablepressure system member therein moving in a direction toward an end wallof the chamber;

FIG. 3 illustrates the chamber of the pressure source of FIG. 2 as themovable pressure system member continues to move in the direction towardthe end wall of the chamber, and contacts an exemplary post of theMFLP-valve associated with the pressure source, causing the MFLP-valveto begin to move in the same direction as the movable pressure systemmember;

FIG. 4 illustrates the chamber of the vacuum source of FIGS. 2 and 3 asthe movable pressure system member moves further in the direction towardthe end wall of the chamber, causing the MFLP-valve to expose a regionof an interior of the chamber between the movable pressure system memberand the end wall of the chamber to an initializing pressure through anexemplary aperture in the end wall of the chamber;

FIG. 4A is a bottom view of an embodiment of a MFLP-valve constructed inaccordance with the principles of the present disclosure;

FIG. 4B is an enlarged cross-section of the MFLP-valve taken along lines4B-4B of FIG. 4A, the MFLP-valve having an annular rib defining a gasketor O-ring to facilitate sealing;

FIG. 5 illustrates the chamber of the pressure source of FIGS. 2-4 asthe movable pressure system member approaches the end wall of thechamber;

FIG. 6 illustrates the chamber of the pressure source of FIGS. 2-5 oncethe movable pressure system member reaches an end of its travel withinthe chamber, and begins to move in a direction away from the end wall,which movement begins to close the MFLP-valve;

FIG. 7 illustrates an exemplary embodiment of a MFLP-valve including ablock secured to an end wall of a pressure chamber secured by a livinghinge to a MFLP-valve membrane and post portion of the MFLP-valve;

FIG. 8 illustrates the MFLP-valve of FIG. 7 in an unsealed condition, asdetected by the interruption of a beam of light directed toward aphotosensor;

FIG. 9 illustrates an alternate embodiment of a MFLP-valve including aMFLP-valve membrane, an integral sealing gasket, a post that extendsthrough an aperture of a wall of a pressure source, and a trigger in theform of a home flag directly connected to the MFLP-valve membrane that,upon actuation of the MFLP-valve membrane from a sealed to an unsealedcondition, interrupts the beam of light directed toward the photosensor;

FIG. 10 illustrates the MFLP-valve of FIG. 9 in an unsealed condition,as detected by the interruption of a beam of light directed toward thephotosensor;

FIG. 11 illustrates a configuration similar to that of FIG. 10, once themovable pressure system member reaches an end of its travel within thechamber;

FIG. 12 is a flowchart depicting operation of a pressure systemfeaturing a vacuum equalization MFLP-valve of the present disclosure;

FIG. 13 is a schematic illustration of an exemplary pressure system,including two MFLP-valves constructed in accordance with the principlesdescribed herein;

FIG. 14 is a side view of an exemplary MFLP-valve constructed inaccordance with the principles herein, where one or more component ofthe MFLP-valve may be fine-tuned in any manner, such as illustrated bythe broken lines, to meet the needs of a particular pressure system withwhich the MFLP-valve is employed;

FIG. 15 is a cross-sectional view of an alternate embodiment wherein anMFLP-valve of the present disclosure is employed in a rigid cap portionof a diaphragm-type pressure source, with a flexible diaphragm portionof the pressure source, under the control of a movable pressure systemmember, illustrated in a first position away from a rigid cap;

FIG. 16 is a cross-sectional view of the embodiment of FIG. 16, with theflexible diaphragm portion of the pressure source, under the control ofthe movable pressure system member, illustrated in a second, homeposition toward the rigid cap, with the movable pressure system membercontacting an exemplary post of the MFLP-valve associated with thepressure source, causing the MFLP-valve to begin to move in the samedirection as the movable pressure system member, resulting in theMFLP-valve exposing a region of an interior of the chamber between theflexible diaphragm portion and the rigid cap of the pressure source toan initializing pressure through an exemplary aperture in the rigid capthat is otherwise closed by the post of the MFLP-valve;

FIG. 17 is a cross-sectional view of another alternate embodimentwherein an MFLP-valve of the present disclosure is employed in aflexible diaphragm portion of a diaphragm-type pressure source, with theflexible diaphragm portion of the pressure source, under the control ofa movable pressure system member, illustrated in a first position awayfrom a rigid cap; and

FIG. 18 is a cross-sectional view of the embodiment of FIG. 17, with theflexible diaphragm portion of the pressure source, under the control ofthe movable pressure system member, illustrated in a second, homeposition toward the rigid cap, with the movable pressure system memberbringing an exemplary post of the MFLP-valve associated with thediaphragm portion of the pressure source into engagement with the rigidcap, causing the MFLP-valve to begin to move in a direction opposite tothe movable pressure system member, causing the MFLP-valve to expose aregion of an interior of the chamber between the flexible diaphragmportion and the rigid cap of the pressure source to an initializingpressure through an exemplary aperture in the rigid cap that isotherwise closed by the post of the MFLP-valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the principles of the present disclosure, a pressuresource, such as a pressure source 10 of a breastmilk expression device,for example, includes a pressure generating chamber 12 having a movablepressure system member 14 therein. The movable pressure system membermay be actuated by an actuator 16, as illustrated in FIG. 1. AMFLP-valve 18 is associated with an end wall of the pressure generatingchamber 12. As used herein, the term “MFLP-valve” refers to a pressuremodification valve that can be configured to be coupled with a sensorflag, either directly or indirectly. The MFLP-valve 18 can be secured ina sealed relationship with an aperture 25 in a wall of the pressuregenerating chamber 12, or can otherwise be positioned as desired on ornear the pressure generating chamber 12 or connected to a connector ortubing extending from the pressure generating chamber 12. In anembodiment, the MFLP-valve 18 can be displaced from a sealed conditionto an unsealed condition relative to the aperture 25 by actuation of themovable pressure system member 14, or reciprocating member, from a firstposition to a second position, the MFLP-valve 18 actuable to anunsealed, open position upon the movable pressure system member 14reaching the second position. By way of example only, the actuation ofthe MFLP-valve 18 from the sealed condition to the unsealed conditionmay be initiated by the movable pressure system member 14 coming intocontact with, or engaging, a post 22 of the MFLP-valve 18 that extendsthrough the aperture 25. As the movable pressure system member 14approaches the aperture 25 associated with the pressure generatingchamber 12, the movable pressure system member 14 engages the post 22.Continued actuation of the movable pressure system member 14 toward theaperture will urge the MFLP-valve 18 from a sealed condition to anunsealed condition relative to the aperture 25.

A “pressure differential” exists when the system pressure inside thechamber 12 differs from the pressure outside of the chamber 12. Forexample, vacuum generating systems, such as medical pumps, may create anegative pressure differential during use. In accordance with theprinciples herein, when the MFLP-valve 18 reaches the unsealedcondition, or active state, relative to the aperture 25, pressuredifferential can be normalized by allowing fluid to flow through theaperture 25. In an embodiment, the fluid can be air and the pressureoutside of the system can be atmospheric pressure. The direction of thefluid moving through the aperture 25 will depend on whether the pressuredifferential is positive or negative. The MFLP-valve 18, or a portionthereof, is responsive to a mechanical force applied to open theMFLP-valve 18 upon movable pressure system member 14 of the pressuresource 10 of the device approaching or arriving at a selected position.In an embodiment, the selected position can be an initializationposition.

In the absence of a MFLP-valve or vent to relieve pressure, it is commonfor pressure generating devices to have some pressure differentialexisting between a pressure generating chamber and a volume outside thepressure generating chamber even when it is believed that a volumedisplacement mechanism of the device has returned to its originalposition. As such, a desirable feature of the MFLP-valves of the presentdisclosure is that when the MFLP-valve 18 is in an unsealed condition(i.e., an open position) relative to the aperture 25, any pressuredifferential existing between a pressure generating chamber and a volumeoutside the pressure generating chamber in the pressure generatingchamber 12 is relieved. Embodiments wherein the pressure generatingchamber 12 generates a negative or positive pressure differentialbetween a pressure generating chamber and a volume outside the pressuregenerating chamber are considered within the scope of the presentdisclosure. By equalizing the pressure within the pressure generatingchamber 12 with pressure outside the pressure generating chamber 12, thepressure generating chamber 12 is returned to a selected pressure, suchas atmospheric pressure, if desired. Operating a breastpump or otherpressure system in a manner that regularly returns the pressuregenerating chamber 12 to a selected pressure enhances the accuracy ofthe pressure system by providing a consistent pressure condition foreach cycle of the system.

As illustrated in exemplary embodiments of FIGS. 2-6, an exemplaryarrangement of structural components of a pressure source 10 as amovable pressure system member 14 thereof approaches an end wall 20 of apressure generating chamber 12 is set forth. The pressure source 10 ofFIGS. 2-6 is a piston-cylinder -type vacuum source. However, the sameprinciples illustrated in FIGS. 2-6 and described herein could beapplied to a diaphragm-type vacuum source, or any other suitable cyclicpressure system in a similar manner.

As illustrated in FIG. 2, the movable pressure system member 14, whichis shown in the form of a piston, but could alternatively be a diaphragmor other movable pressure system member, is actuated, such as by anactuator 16 (represented schematically in FIG. 1, but not shown in FIGS.2-6), which may be a motor or driven by a motor or other applicablemechanical displacement device. The movable pressure system member 14moves in a direction toward the end wall 20 of the vacuum generatingchamber 12, as represented by the vertical up-arrow in

FIG. 2.

As illustrated in FIG. 3, the movable pressure system member 14 caninitiate contact with a post 22 associated with the MFLP-valve 18 duringthe course of a pressure cycle. The post 22 may be in the form of aprotrusion, such as an exemplary cylindrical protrusion, that extendsfrom a MFLP-valve membrane 24 that normally covers over an aperture 25provided in any suitable location, such as in the end wall 20 of thevacuum generating chamber 12, which aperture 25 can be seen in FIG. 4.In an alternative embodiment, the post 22 may be located on or connectedto the movable pressure system member 14. The continued movement of themovable pressure system member 14 in the direction toward the end wall20 following initial contact with the post 22 can cause the MFLP-valvemembrane 24 of the MFLP-valve 18 to move away from the end wall 20 ofthe pressure generating chamber 12, as illustrated in FIGS. 4 and 5.

To seal the aperture 25, the MFLP-valve membrane 24 may include a rib,such as an annular rib, that defines a gasket 24 a, which may be in theform of an O-ring, as illustrated in FIGS. 4A and 4B. Returning to FIGS.3 and 4, for the MFLP-valve 18 to seal the aperture 25, the membrane 24sealingly engages a wall of the pressure generating chamber 12 about aperimeter of the aperture 25. In sealingly engaging a wall of thepressure generating chamber 12 about a perimeter of the aperture 25, thewall may be an end wall of the pressure generating chamber 12 in whichthe aperture 25 is disposed. The wall of the pressure generating chamber12 may have surface treatments or features surrounding or near theaperture 25 that complement the composition, size and shape of themembrane 24 (which may include the gasket 24 a), enabling a tighter sealat the wall of the pressure generating chamber 12. The surface of thewall of the pressure generating chamber 12 that surrounds the aperture25 may be sloped inward toward or outward away from the aperture 25,such that the aperture 25 can be sealed with a flat gasket 24 a thatengages the sloped surface. Alternately, the surface of the wall of thepressure generating chamber 12 that surrounds the aperture 25 may besloped and the gasket 24 a may have a curved shape that is complementaryto the sloped surface.

As illustrated in the exemplary embodiment of FIG. 6, the movablepressure system member may reverse direction upon reaching a selectedposition within the pressure generating chamber. The selected positionmay be near or at the end wall of the pressure generating chamber. Themovable pressure system member may also change direction for example,upon the system responding to a parameter other than the MFLP-valve'sflag state. This parameter could be a selected minimum volume, anelectrical/mechanical condition regarding the actuation or the state ofa secondary sensor. As the movable pressure system member reverses, itmay also cause the MFLP-valve to begin to move back toward the aperture25 in the end wall 20 of the vacuum chamber 12. A force such as gravityor another force imposed on the MFLP-valve by the system's geometry mayfacilitate movement of the MFLP-valve 18 back toward a closed, sealedcondition as the movable pressure system member 14 continues to move ina direction away from the end wall 20, i.e., as the movable pressuresystem member 14 moves away from a position consistent with a minimumvolume within the pressure chamber 12. When the movable pressure systemmember 14 moves sufficiently away from the end wall 20 of the pressurechamber 12 as to lose contact with the post 22 of the MFLP-valve 18, theMFLP-valve membrane 24 of the MFLP-valve 18 returns to its positionclosing over the aperture 25, i.e., the position of the MFLP-valve 18illustrated in FIG. 2.

Continued movement of the movable pressure system member 14 away fromthe end wall 20 generates pressure within the pressure chamber 12 whilethe MFLP-valve is closed. This pressure may be negative pressure,commonly referred to as vacuum. The vacuum pressure may help to ensure aseal between the MFLP-valve membrane 24 and the end wall 20.

Turning to FIGS. 7 and 8, an exemplary alternative MFLP-valve 26 is setforth. The alternative MFLP-valve 26 includes an anchoring feature 28secured to the end wall 20 of the pressure chamber 12. The MFLP-valvemembrane 24 of the MFLP-valve 26 may be secured to the anchoring feature28 by a living hinge 30. When the movable pressure system member 14contacts the post 22 of the MFLP-valve 26 and continues to move in adirection toward the end wall 20 of the MFLP-valve chamber 12, theMFLP-valve membrane 24 is moved to an unsealed condition. Due to itssecurement to the anchoring feature 28, the MFLP-valve membrane 24 maybe moved to a position at an angle greater than 0° relative to the endwall 20 when in the unsealed condition. This angled position of theMFLP-valve membrane 24 may be advantageous because it provides anopportunity to detect a condition of the MFLP-valve's 26 flag consistentwith the movable pressure system member 14 having reached a selectedposition. The selected position may be a home position. As used herein,a “home position” refers to a position of the movable pressure systemmember 14 that is closest to the end wall 20 of the pressure chamber 12,or a position consistent with the pressure chamber 12 having a minimalvolume in the range of travel of the movable pressure system member 14.If desired, the position sensing function at the MFLP-valve may beselectively decoupled from the pressure modification of the MFLP-valve.

The home position of the movable pressure system member 14 may bedetected, for example, by a photo sensor 32 that detects interruption ofa beam of light L projected by a light source 34 toward the photo senor32, as illustrated in the exemplary embodiment of FIG. 8. The beam oflight L may be interrupted by the main body of the MFLP-valve membrane24. Alternatively, the beam of light L may be interrupted by a home flag36. The home flag 36 may be directly or indirectly connected to theMFLP-valve membrane 24. As illustrated in FIGS. 1, 9 and 10, such a homeflag 36 may be configured to trigger a signal to the controller of thepressure system to at least one of (1) initiate or otherwise modifyoperation of the pressure source upon motion of the MFLP-valve membrane24 between a sealed condition and an unsealed condition; and (2) verifya position of the movable pressure system member 14 of the pressurechamber 12.

Various alternate means for detecting at least one of an unsealedcondition of the MFLP-valve membrane 24, and a home position of themovable pressure system member 14, may be employed. For instance,instead of interrupting a light beam, the home flag 36 could have anaperture or interruption therein, through which a light beam only passeswhen the home flag 36 is in a position consistent with the MFLP-valvemembrane 24 being in an unsealed condition and/or the movable pressuresystem member 14 being in the home position. Instead of a light beam,the home flag 36 may be made of a material, such as a conductivemetallic material, that completes a circuit, or breaks a circuit, whenin a position consistent with the MFLP-valve membrane 24 being in anunsealed condition and/or the movable pressure system member 14 being inthe home position. The presence of the home flag 36 in a positionconsistent with the MFLP-valve membrane 24 being in an unsealedcondition and/or the movable pressure system member 14 being in the homeposition may be detected by a number of alternative sensing mechanisms,for example a magnetic sensor, a proximity switch, or a microswitch.

Alternately, the home flag 36 may comprise a fluid, such as in a gasphase or a liquid phase, wherein the fluid is displaced from a firstposition to a second position upon movement of the MFLP-valve membrane24 between a sealed and an unsealed condition and/or the movablepressure system member 14 being in the home position. The movement ofthe fluid could be detected, which could serve as a signal to thecontroller of the pressure system to at least one of (1) initiate orotherwise modify operation of the pressure source upon motion of theMFLP-valve membrane 24 between a sealed condition and an unsealedcondition; and (2) verify a position of the movable pressure systemmember 14 of the pressure chamber 12.

Instead of detecting displacement of the MFLP-valve membrane 24 itselfor of a home flag 36 directly or indirectly connected to the MFLP-valvemembrane 24, the position of the movable pressure system member 14 maybe detected, such as through a window in a wall of the pressuregenerating chamber 12 in conjunction with the action of the MFLP-valve.When the movable pressure system member 14 is detected, a signal may besent to a controller. In combination with the action of the MFLP-valve,detection of the movable pressure system member 14 may also be used toinitiate or change the motion of the movable pressure system member 14,allowing continued operation of the pressure system. The detection ofthe movable pressure system member 14 and the opening of the MFLP-valvemembrane 24 may be coordinated to occur in a complementary way, but theyneed not occur simultaneously.

The drawing figures illustrate an aperture 25 located at the end of thepressure generating chamber 12 that coincides with an end of range ofmotion of the movable pressure system member 14. This end of range ofmotion may be consistent with a minimum volume within the pressuregenerating chamber 12. While this “home position” of the movablepressure system member 14 may be considered the beginning of a stroke orcycle, the aperture 25 may alternately be positioned to trigger anywherealong the pressure cycle. For example, the aperture 25 may be located ata position of the pressure generating chamber 12 that coincides with anopposite end of range of motion of the movable pressure system member14, consistent with a maximum volume within the pressure generatingchamber 12. Depending on the construction and operation of the givenpressure generating chamber 12 and movable pressure system member 14,this position may be the middle of a pressure cycle or the end of astroke of the movable pressure system member 14. The MFLP-valve 18 maybe placed at any location in the system that provides a beneficialposition indication, or relief of pressure differential.

The MFLP-valve 18 may have a region 24b (see FIGS. 10 and 11), such as aperimeter region, that, like the anchor 28 of the embodiment illustratedin FIGS. 7 and 8, serves to fix the MFLP-valve 18 to a wall of thepressure generating chamber 12. A MFLP-valve membrane portion 24 of theMFLP-valve 18 remains sufficiently flexible to selectively move thegasket 24 a out of sealing engagement with the perimeter of the aperture25 when the post 22 of the MFLP-valve 18 is engaged by the movablepressure system member 14. The MFLP-valve 18 may be attached to thepressure system in number of ways, including but not limited tofasteners, retaining clips, barbs, clamps or adhesives. It is importantthat the attachment method positions the sealing element in such a waythat it can engage the aperture in the pressure system at theappropriate time, as previously discussed. The attachment method, inconjunction with the composition and geometry of the MFLP-valve, may bedesigned to allow the MFLP-valve to open in response to a selectedpressure, irrespective of the position of mechanical elements in thesystem.

As illustrated in the exemplary embodiment of FIG. 12, the movablepressure system member 14 approaches the MFLP-valve 18 during a returnstroke. Next, the movable pressure system member 14 contacts the post 22of the MFLP-valve 18. Then, the home flag 36, referred to in the flowdiagram as a “home position flag”, moves toward a home position sensoras a MFLP-valve seal is pushed to an unsealed condition. The unsealingof the aperture 25 results in the pressure chamber 12 beginning toequalize through the aperture 25.

In an embodiment wherein the pressure system is a breastpump, themovable pressure system member can be a piston or diaphragm, and thepressure chamber can be a cylinder, the pressure chamber 12 equalizes(returns to a selected pressure), prior to the home flag 36 triggeringthe home position sensor (though it is recognized that the home flag 36could trigger the home position sensor at any time subsequent to contactbetween the movable pressure system member 14 and the post 22 of theMFLP-valve 18). Next, the home flag 36 triggers the home positionsensor. Thereafter, the movable pressure system member 14 reverses, andcommences its draw stroke. This can cause the home position flag 36 tomove out of communication with the home position sensor. After themovable pressure system member 14 disengages from the post 22 of theMFLP-valve 18, the MFLP-valve 18 returns to a sealed condition with theaperture 25 of the pressure chamber 12. This seal may be enhanced by thenegative pressure increase as the movable pressure system member 14continues its draw stroke. The MFLP-valve 18 and its associated homeposition flag 36, are then ready for the next cycle. Ultimately, themovable pressure system member 14 draws to its intended excursion, thenbegins a return stroke and the cycle repeats.

Referring to FIG. 13, a schematic illustration of a pressure source 10is disclosed. The pressure source 10 can include multiple MFLP-valves 18a and 18 b constructed in accordance with the principles disclosedherein. A single MFLP-valve 18 could be used instead of two MFLP-valves18, or additional MFLP-valves 18 could be provided, if desired. Thepressure source 10 may be configured to selectively activate one or moreMFLP-valves based on the systems mode of operation. Each MFLP-valve maybe independently configured in terms of geometry, material, tuningcondition, or the presence of a position indicating flag. For example,in FIG. 13, MFLP-valve 18 a has a vented region that can expand andcontract based on the mechanical action of pressure source 10, whileMFLP-valve 18 b has one or more nonexpandable vents that are connectedto and disconnected from the pressure source 10 based on mechanicalaction. Having multiple MFLP-valves with differing configurations, eachof which can be independently activated or deactivated, may bebeneficial in a system that includes multiple modes of operation.

Turning to FIG. 14, while an exemplary MFLP-valve 24 is illustrated insolid lines, various features of the MFLP-valve 24 can be adjusted totune the accuracy, precision, sensitivity, or other parameter associatedwith the MFLP-valve 24. This adjustment may occur as a factory setting,or it may occur after initial manufacturing, as part of the function ofthe overall system. If a pressure system, such as a breastpump, isconfigured to offer selectable or alternative modes of operation for auser, it may be beneficial to incorporate a MFLP-valve, constructed inaccordance with the principles herein, having performancecharacteristics which can be selectively tuned as a result of useraction. This tuning may be accomplished by configuring the system toreposition, compress, expand, trim, energize, or otherwise modify aportion of the MFLP-valve, or an interface associated with theMFLP-valve, as a result of user action. Various examples of tunablefeatures of the MFLP-valve 24 are represented by dashed lines in FIG.14. These include, but are not limited to, the home flag 36 thatinteracts with the position switch or position sensor, the element(s)that attach the MFLP-valve to the rest of the system, the gasket 24 athat surrounds and/or is inserted into the relief orifice, and the post22 that contacts the movable pressure system member 14. For instance,the home flag 36 may be varied in height, width, or any other dimensionin order to adjust its ability to be detected. Another example, thegasket 24 a may be an O-ring or may have a different shape and thediameter and/or size of the gasket 24 a may be varied to best achievesealing around an aperture 25. The mating properties between the gasket24 a and the wall surrounding the aperture 25 may be varied. As yetanother example, the height of the post 22 may be altered to vary whenthe post 22 is impacted by the movable pressure system member 14. Inaddition to the geometric properties of the various elements of theMFLP-valve 24, the material properties of any of the elements of theMFLP-valve 24 may be altered in order to tune parameters associated withthe MFLP-valve 24. For example, the compressibility, stiffness, orelasticity of the post 22 may be altered to change the interactionbetween the post 22 and the movable pressure system member 14 and/or thetiming of the pressure cycles. Elastic, rubber, spring-like material, orany other expandable material could be used in the MFLP-valve 24. TheMFLP-valve may be a single component or it may be composed of more thanone component or material. In addition, the performance of theMFLP-valve 18 may be tuned by altering the elements of pressure source10 with which the MFLP-valve 18 interacts.

Implementation of an MFLP-valve of the present disclosure indiaphragm-type pressure sources will now be described. As illustrated inFIG. 15, a diaphragm-type pressure source 40 may include a flexiblediaphragm membrane 42 and a rigid cap 44. A movable pressure systemmember 46, such as a piston, actuates the flexible diaphragm membrane 42between a first position away from the rigid cap 44 and a secondposition toward the rigid cap 44. The movable pressure system member 46may be provided with a rigid engagement member 48 that passes throughthe surface of the flexible diaphragm membrane 42. An MFLP-valve 50 isconnectable in any suitable manner, such as by providing connectingmembers 45 that extend through the cap 44. Alternatively, the connectingmembers can be securely fitted within the volume of the rigid cap 44.

As illustrated in FIG. 16, when the movable pressure system member 46actuates the flexible diaphragm membrane 42 to the second positiontoward the rigid cap 44, the rigid engagement member 48 contacts a post52 of the MFLP-valve 50. Due to the engagement of the rigid engagementmember 48 with the post 52 of the MFLP-valve 50, further movement of themovable pressure system member 46 toward the rigid 44 causes the post 52of the MFLP-valve 50 to move out of sealed engagement with a ventaperture 55 in the rigid cap 44. The unsealing of the vent aperture 55results in the pressure chamber 41, and specifically the region betweenan inner wall of the rigid cap 44 and the flexible diaphragm membrane42, equalizing through the aperture 55. The MFLP-valve 50 may beprovided with a flag or other sensor-trigger to facilitate detectionthat the flexible diaphragm membrane 42 or the movable pressure systemmember 46 has reached the home position. Alternately, a portion of thesurface of the MFLP-valve 50 itself, such as an apex 56 of an operablecover of the MFLP-valve 50, may serve as the flag or other sensortrigger. By way of example only, actuation of the post 52 of theMFLP-valve 50 and movement out of sealed engagement with the ventaperture 55 in the rigid cap 44, the apex 56 may interrupt a beam oflight from a light source 58 normally detected by a photosensor 60.Alternately, a Hall effect position sensor or other position sensorcould be used in concert with the apex or other surface of theMFLP-valve 50, or with a flag associated with the MFLP-valve 50 todetect that the flexible diaphragm membrane 42 or the movable pressuresystem member 46 has reached the home position.

An alternate embodiment of the use of an MFLP-valve of the presentdisclosure in a diaphragm-type pressure source is illustrated in FIGS.17 and 18. In this embodiment, a diaphragm-type pressure source 70includes a flexible diaphragm membrane 72 and a rigid cap 74. Instead ofthe MFLP-valve being provided in the rigid cap 74, in this embodiment anMFLP-valve 76 is provided in the flexible diaphragm membrane 72. Theflexible diaphragm membrane 72 is actuated by a movable pressure systemmember 78, such as a piston, from a first position away from the rigidcap 74, as illustrated in FIG. 17, to a second, home position toward therigid cap, as illustrated in FIG. 18.

The MFLP-valve 76 is provided with a post 80 that extends from anoperable cover of the MFLP-valve 76, through a vent aperture 81 in theflexible diaphragm membrane 72. The post 80 seals the vent aperture 81when the post 80 is not engaging the rigid cap 74. During actuation bythe movable pressure system member 78 of the flexible diaphragm membrane72 toward the home position, as illustrated in FIG. 18, the post 80 ofthe MFLP-valve 76 makes contact with the rigid cap 74, and continuedactuation of the movable pressure system member 78 causes the post 80 tounseal the vent aperture 81, thereby equalizing pressure in the spacebetween the flexible diaphragm membrane 72 and the rigid cap 74.

Because the MFLP-valve 76 of this embodiment opens underneath theflexible diaphragm membrane 72, it may be more involved to arrange asensor that can be used to detect the arrival of the flexible diaphragmmembrane 72 or the movable pressure system member 78 at the homeposition. However, a sensor, such as a photoelectric sensor or a Halleffect position sensor, could be arranged within the diaphragm membrane72. Alternately, a contact pad may be provided on the underside of therigid cap 74 in registration or alignment with the post 80 of theMFLP-valve 76, and each time the post 80 contacts the contact pad, asignal could be communicated to a controller indicative of arrival ofthe flexible diaphragm membrane 72 or the movable pressure system member78 at the home position.

While the components and features disclosed herein are illustrated anddescribed with respect to certain specific embodiments, it will beunderstood that combinations and sub-combinations of those componentsand features can be accomplished within the scope of this specification,and such combinations and sub-combinations should also be considered asdisclosed herein.

The embodiments herein have been described and shown for purposes ofillustration only, and are not to be construed as constituting anylimitations of the present principles. Modifications will be obvious tothose skilled in the art, and all modifications that do not depart fromthe spirit of the principles herein are intended to be included withinthe scope of the appended claims. Those skilled in the art willappreciate that the conception, upon which this disclosure is based, mayreadily be utilized as a basis for the designing of other structures,methods and systems for carrying out the several purposes of the presentprinciples.

Therefore, the foregoing is considered as illustrative only of theprinciples herein. Further, since numerous modifications and changeswill readily occur to those skilled in the art, it is not desired tolimit the principles to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the principles describedherein.

1-15. (canceled)
 16. A medical pressure system including a MFLP-valvecomprising: a MFLP-valve configured to extend into a fluid flow sectionof the medical pressure system, the MFLP-valve including an operablecover and a post connected to the operable cover, the post configured toengage an aperture of the pressure system during operation of thepressure system; a movable pressure system member; and a diaphragmmember having a rigid engagement member; wherein the operable cover viathe post is configured to selectively open the aperture based onselective engagement with a movable pressure system member in thesystem, engagement occurring when the rigid engagement member isactuated by the movable pressure system member and contacts the post.17. The medical pressure system including a MFLP-valve of claim 16,wherein the operable cover is connectable to a pressure chamber withinthe medical pressure system and operably connected to a flag configuredto indicate a position of the movable pressure system member in thepressure system.
 18. The medical pressure system including theMFLP-valve of claim 17, the flag configured to selectively engage asensor dependent on a position of the flag relative to the position ofthe movable pressure system member.
 19. The medical pressure systemincluding the MFLP-valve of claim 17, further comprising one or morevents configured to enable fluid flow into or out of the pressurechamber within the pressure system.
 20. The medical pressure systemincluding the MFLP-valve of claim 19, the vents formed in the operablecover, the vents further defined by at least one of expandable vents andnonexpandable vents.
 21. The medical pressure system including theMFLP-valve of claim 17, the flag connected to and extending from theoperable cover.
 22. The medical pressure system including the MFLP-valveof claim 17, further comprising a breastpump, and wherein the flag isconfigured to selectively engage a sensor when the movable pressuresystem member of the pressure system is in a desired position. 23.(canceled)
 24. The medical pressure system including the MFLP-valve ofclaim 16, wherein the MFLP-valve is constructed so as to change shape inresponse to engagement by the movable pressure system member, and eitherthe shape change creates an opening that relieves pressure in thepressure system or the shape change indicates a change in the positionof the movable pressure system member.
 25. The medical pressure systemincluding the MFLP-valve of claim 16, wherein the MFLP-valve isintegrally formed within a surface of the pressure system.
 26. Themedical pressure system including the MFLP-valve of claim 16, whereinthe MFLP-valve is configured for selective tuning to adjust fluid flowin the system based on a state of operation of the system.